Fork lift attachment for a work vehicle



July 10, 1956 'r. J. DUNN ETAL FORK LIFT ATTACHMENT FOR A WORK VEHICLE 3 Sheets-Sheet 1 Filed May 18, 1954 l- 4 4 c a P m 2 m o O m w VN 5 O J 0 0 Z 5 V B 0 w H M m. u u f 9 L W 9 n 3 la a I 7 L J w w 7) T 6 f 0, M W W. l b I 7 6 MI M a A 7 I) F 5 z 5 7 2 H 3 n 2 L. O\ L. 7 U a 3 1L. In j V 5 a M 9 1. N H @F n QT 3 f E 2 UHF y v J4 w a z a 9 7 2 a a 2 o 2 4 6 a 4 F July 10, 1956 T. J. DUNN EIAL 2,754,020 FORK LIFT ATTACHMENT FOR A WORK VEHICLE Filed May 18, 1954 3 Sheets-Sheet 2 INVENTOR. 7 /0 445 J'- DU/V/V Alsie's/er W- DAV/5 July 10, 1956 T. J. DUNN ETAL FORK LIFT ATTACHMENT FOR A WORK VEHICLE Filed May 18, 1954 3 Sheets-Sheet 3 INVENTOR. 70 THOMAS J'- OU/V/V Hszeser w. 041/15 60 y err-omen United States Patent G FQRK LIFT ATTACHMENT FOR A WORK VEHICLE Thomas J. Dunn and Herbert W. Davis, Hackettstown, N. J.

Appiication May 1S, 1954, Serial No. 436,536 6 Claims. (Ci. 214-674) This invention relates to a fork lift attachment for a work vehicle.

An object of the invention is to provide a fork lift attachment which is simple in construction and which is connectible to the frame of a work vehicle with ease and facility.

Another object of the invention is to provide a fork lift attachment which is wheel supported and which is connectible to and disconnectible from the frame of a work vehicle.

A further object of the invention is to provide a fork life attachment in which means is provided for shifting the elevated load rearwardly over the vehicle frame-to an extent such that the weight of such load is distributed over the vehicle.

Other and further objects of the invention will become apparent from the following description taken in conjunction with the accompanying drawings, in which:

Figure l is a vertical cross sectional view taken longitudinally through the forward portion of a work vehicle of the caterpillar type provided with a fork lift attachment constructed in accordance with the present inventron.

Figure 2 is a horizontal cross sectional view taken on the line 22 of Figure 1.

Figure 3 is a perspective view of the fork lift attachment of the present invention, parts of the guide rails being broken away, and with the fork elements and actuating mechanism omitted.

Figure 4 is a side elevational View of a work vehicle of the caterpillar type with the fork lift attachment of the present invention mounted thereon and with the fork elements of such attachment in position beneath a load to be elevated by the vehicle.

Figure 5 is a partial side elevational view of the assembly of Figure 4, the full lines showing the fork elements of the attachment in an elevated position supporting a load, and the dotted lines showing the attachment in tilted position toward the operator of the vehicle.

Figure 6 is a side elevational view of the assembly or Figure 4, showing the fork elements of the attachment in elevated position supporting a load with the attachment in tilted position to an extent such as to distribute the load over the vehicle.

Figure 7 is an enlarged cross sectional detail view taken on the line 77 of Figure 2.

Referring to Figures 1 and 2, the numeral 16 designates the horizontally disposed frame of the work vehicle, the frame including spaced side members 2, a cross member 3 intermediate the ends of the side members, and a rear cross member 4, with no cross member connecting the front ends of. the side members 2. The thus described frame is unobstructed inwardly from its front end to a point spaced from the rear end. The frame 13 is supported upon a pair of traction units or endless track assemblies 17, only one being shown, extending longitudinally of and substantially parallel to the side members 1 and 2 and spaced respectively outwardly of such side members.

A fork lift attachment of the present invention and designated by the numeral 11 is detachably connected to the vehicle frame 16. The attachment includes a main frame 12 which has a pair of side bars 13, the front ends of the side bars 13 being connected together by a crossbar 14. In connecting the frame 12 of the attachment to the vehicle frame 16, the frame 12 is positioned so that the crossbar 14 faces the open front end of the vehicle frame 16 and is then moved to cause the frame 12 to rest upon the vehicle frame 16, with the appurtenances for operating the fork lift member extending between the side bars 13, whereupon the frame 12 of the attachment is moved backwardly along the vehicle frame 16 until the fork elements of the attachment are adjacent the open end of the vehicle frame. At this point the frame 12 of the attachment is detachably secured to the vehicle frame 16 by means of fastening elements or bolts extending through complemental means or holes 7- formed in the side bars 13 of the attachment frame 12 in registry with complemental means or holes 6 formed in the side members 2 of the vehicle frame 12.

The work vehicle is provided with a suitable source of hydraulic fluid under pressure, designated at 18.

The respective side bars 13, 13 of the attachment main frame 12 are provided at their intermediate portions with depending plate elements 19, 19. Designated generally at 29 is an attachment subframe comprising a transversely extending vertical plate member 21 to which is rigidly secured the respective longitudinally extending vertical plate members 22, 22, the plate members 22 being located adjacent the respective longitudinal side bars 13, 13 of the attachment frame 12.

Rigidly secured to the respective opposite end portions of the transverse vertical plate member 21 of the attachment subframe 20 are the respective substantially vertical, opposing, channeled guide rails 23, 23, said guide rails being of any suitable cross sectional shape, for example, being V-shaped, as is clearly shown in Figure 2.

Designated at 24 is a conventional fork lift member which is provided with a pair of horizontally disposed fork elements 25, 25, the fork elements being carried by the vertically extending rail members 26, 26, slidably received in the respective vertical guide rails 23, 23. Each of the rail members 26 has affixed thereto a rail element 27 which is disposed between a complemental rail member 26 and a guide rail 23, to provide an extended range of vertical movement of the fork lift member 24. For example, the fork lift member 24 is provided with a fluid pressure cylinder 28 having pulleys 29 mounted on the end of its piston which is cooperatively arranged with respect to a cable 30 which is connected at one end to a transverse bar member 31 connecting the top ends of the rails 23, 23 and which passes over pulleys 32 journaled to the stationary transverse support member 33 secured to the upper portions of rails 23, 23. The cable 30 may be connected at its lower end to a transverse bar member 35 secured to the rail elements 27, 27.

The cylinder 28 is connected in a conventional manner to the hydraulic fluid source 18 through suitable control valves, and admission and withdrawal of such hydraulic fluid to the cylinder causes the raising and lowering of the fork member 24.

The telescoping rail structure, as well as the conduit connections for the cylinder 28 are conventional and form no part of the present invention.

Secured to and extending through the lower forward portions of the longitudinal vertical plate members 22 of attachment subframe 20 is a transverse shaft 36. Designated at 37, 37 are respective link bars pivotally connected to the ends of the shaft 36 outwardly adjacent the respective longitudinal plate members 22, 22. The lower ends of the link bars 37 are pivotally connected at 38, 38 to the lower rear portions of the depending plate members 19, 19. Designated-at 39 is a fluid pressure cylinder pivotally connected at 40, between a pair'of upstanding bracket members 41, 41- mounted on the intermediate portion of the transverse frame member 14. The p1ston 42 :of the cylinder 39 is pivotally connected'at 43 to the intermediate portion of the transverse shaft 36, whereby the attachment subframe 20 may be swung on the link bars 37, 37 by retracting .or extending the piston 42 from the cylinder '39. The opposite ends of the cylinder 39 are connected by respective conduits 44 and 45- through a control valve 46 to the respective high pressure and low pressure ports of-the fluid pressure source 18. Suitable valve means, not shown, are provided for controlling the direction of flow of the hydraulic fluid through the conduits 44 and 45, whereby the movement of the piston 42 may be. controlled, as desired, by the operator.

Designated at 47, 47 are respective fluid pressure cylinders which are pivotally conneced at 48,. 48 to the respective rearward portions of the plate members 22, 22. The pistons 50, 50 of the cylinders 47 are pivotally connected at 51, 51 to the respective lower rearward portions of the plate members 19, 19-, the cylinders being thereby spaced longitudinally but being substantially parallel to the respective link bars 37, 37. The upper portions of the cylinders 47 are connected together by a conduit 52 and the lower portions of said cylinders are connected together by a conduit 53. Conduits 52 and 53 are connected through the control valve 46 to the high pressure and low pressure ports of the fluid source 18 by respective conduits 54 and 55, conventional valve means, not shown, being provided for controlling the direction of flow of hydraulic fluid through the. conduits 54 and 55. Thus, the cylinders 47, 47 define extensible links which may be employed to control the tilting of the attachment subframe 20 around the pivot axis defined by the shaft 36. At thesame time, the extensible links defined by the cylinders 47, 47 are swingable with the. link bars 37,37 when the attachment subframe 20 is rotated on link bars 37, 37 by the action of the cylinder 39.

The control valve 46 is provided with a control plate 55"to which is connected a link rod 56 having a hooked end 57 which is engageable by a cam lever 58 pivoted to the main attachment frame 12 and being locked against rotation by contact with one of the rails 26 of fork member 24 when the fork member is in its lowered position, shown in Figure 1, thus locking the control plate 55 when said fork member is in its lowered position. The controlplate 55' is closed in its locked position so that it cannot be opened as long as the fork member 24 is in its lowered position, shown in Figure 1, thereby preventingoperat-ion of the cylinders 39 and 47, 47 at this time. The lockingrod 56 is released when the fork member 24 is elevated, for example, to the position shown in Figure 5, whereby the attachment subframe 20 may be swung without causing any damage to the guide rails 23 of the fork member 24.

Designated at 60 is a caster which is pivotally connected to a transverse shaft 61 mounted inthe rearward end portion of the attachment main frame 12, said caster having the downwardly convergent supporting arms 63, 63, whose intermediate portions are connected byrespective link bars 64 to the intermediate portions of the link arms 37, the connections of the link bars 64 to the link arms j g shown .at65. The pivotal connections 65 are slidable in slots 66 provided in the link bars 37.

The caster 60 is provided on the opposite sides of the caster wheel 68 with respective ground engaging shoe members 69 to prevent the caster wheel 68 from sinking into the ground when a heavy load is carried on the fork lift member, whereby the device may be employed on relatively soft ground.

As will be apparent from Figure 1, when the link arms. 37 are rotated clockwise in Figure 1 around theippiyotal connections 38, the link members 64 act on the caster 60 to raise the caster from its substantially vertical position, shown in Figure 1, toward a substantially horizontal position, such as is shown in dotted view in Figure 1.

The fluid cylinders 47 pivotally connected respectively to the plate members 22 of the attachment subframe 20 and the plate members 19 ofthe attachment main frame 12 connect the su-bframe 20 to the main frame 12 for tilting back and forth movement, while the cylinder 39 connected to the shaft 36 carried by the plate members 22 of the attachment subframe 20 connect the subframe 20 to the main frame 12 for longitudinal back and forth movement upon execution of the subframe back'tilting movement.

In operation, the device is initially arranged as shown in Figures 1 and 4, and the fork elements 25 are placed beneath the load, shown in dotted view at 66. The hydraulic fluid-cylinder 28 is then operated to lift the load, for example, to the position of Figure 5, thereby contracting the guide rail structure defined by the rails 27 and-'26 within the rails' 23. As above explained,'-this releases the valve plate 55, and allows the valve 46 to be opened. The attachment subframe 20 may then be swung rearwardly on thelink arms 37, 37 by operating the hydraulic cylinder 39, and similarly, the load may be tilted rearwardly over the wheel base of the work vehicle by operating the hydraulic cylinders 47, 47 to cause the attachment subframe 20 to be rotated from the position thereof shown'in Figure 5 to .the position thereof shown in Figure 6. Therefore, the load may be both elevated and moved rearwardly with respect to the center of gravity of the work vehicle, the amount of movement being sufficient to bring the center of gravity of the load substantially over the wheel base of the work vehicle.

When the load is to be deposited, the attachment subframe 20 is rotated forwardly by means of the fluid pressure cylinders 39 and 47, 47 to bring the rails 23, 23 and the associated rails 26 and 27 to substantially vertical positions at the front of the work vehicle, after which the load may be lowered by means of the cylinder 28 and deposited on the ground.

Respective stop plates 70, 70 are rigidly secured on the end portions of the side bars 13, 13 of the attachment mainframe .12,said stop plates extending vertically and being formed with seats to receive the opposite ends of the transverse shaft member 36 when the attachment subframe 20 is in the normal positionthereof shown in Figure 4, namely, when the guide rails 23, 23 and associated rails 26 and 27 are vertical, whereby the attachment subframe 20is positively supported when the fork lift member 24 is in its'loading or unloading position.

What is claimed is:

1. Ida workvehic'le, a pair of traction units, a horizontally' disposed frame extending longitudinally "of and carriedby said units, said frame including spaced'side members and being unobstructed inwardly from its front end to a-point-spaced from its rear end, and a fork lift attachment having-a main frame including spaced side barstrslidable along the nmobstructed portion of said first nameduframe side members, means formed .on .said side bars selectively, registrable with complemental means formed on said side members responsive to'sliding movement of said side bars along the unobstructed portionof said side members, and detachable fastening elements extending through. the registering complemental means of said 'side' bars and side members for securing said lift attachment frame at its selected position of movement to said'first'named frame.

2! In awork'vehicle, a pair of traction units, a horizontally disposed frame extending longitudinally of and can-led by said "units, said frame including spaced side members and beingunobstructed inwardly from its front end itoapointrspaced from'its rear end, and a fork liftattachment: havingna :wheel supported frame including spaced-aside ibarstslidablenlong the unobstructed portion ofisaidfirst namediframe :side' members, means formed on said side bars selectively registrable with means formed on said side bars responsive to sliding movement of said side bars along the unobstructed portion of said side members, and detachable fastening elements extending through the registering complemental means of said side bars and side members for securing said lift attachment frame at its selected position of movement to said first mentioned frame, said wheel being connected to said attachment main frame for movement from its supporting position to a non-supporting position.

3. In a work vehicle, a pair of traction units, a horizontally disposed frame extending longitudinally of and carried by said units, said frame including spaced side members and being unobstructed inwardly from its front end to a point spaced from its rear end, and a fork lift attachment having a main frame including spaced side bars slidable along the unobstructed portion of said first named frame side members, means formed on said side bars selectively registrable with complemental means formed on said side members responsive to sliding movement of said side bars along the unobstructed portion of said side members, and detachable fastening means extending through the registering complemental means of said side bars and side members for securing said lift attachment frame at its selected position of movement to said first mentioned frame, said attachment including a subframe carrying a fork lift member assembly surmounting said attachment main frame and connected to the last mentioned frame for tilting back and forth movement and for longitudinal back and forth movement upon execution of its back tilting movement.

4. In a work vehicle, a pair of traction units, a horizontally disposed frame extending longitudinally of and carried by said units, said frame including spaced side members and being unobstructed inwardly from its front end to a point spaced from its rear end, and a fork lift attachment having a main frame including spaced side bars slidable along the unobstructed portion of said first named frame side members, means formed on said side bars selectively registrable with complemental means formed on said side members responsive to sliding movement of said side bars along the unobstructed portion of said side members, detachable fastening elements extending through the registering complemental means of said side bars and side members for securing said lift attachment frame at its selected position of movement to said first mentioned frame, said attachment including a subframe surmounting said attachment main frame and connected to said last mentioned frame for tilting back and 6 forth movement, and for longitudinal back and forth movement upon execution of its back tilting movement, and a fork lift member assembly connected to said subframe for up and down movement.

5. In a work vehicle, a pair of traction units, a horizontally disposed frame extending longitudinally of and carried by said units, said frame being unobstructed inwardly from its front end to a point spaced from its rear end, and a fork lift attachment having a wheel supported frame slidable along and selectively connectible to the unobstructed portion of said first named frame, said attachment including a subframe carrying a fork lift mem her assembly surmounting said attachment main frame and connected to the last mentioned frame for tilting back and forth movement and for longitudinal back and forth movement upon execution of its back tilting movement, the wheel being connected to said attachment main frame for movement from its supporting position to a non-supporting position upon execution of the longitudinal back movement of said subframe.

6. In a work vehicle, a pair of traction units, a horizontally disposed frame extending longitudinally of and carried by said units, said frame being unobstructed inwardly from its front end to a point spaced from its rear end, and a fork lift attachment having a wheel supported frame slidable along and selectively connectible to the unobstructed portion of said first named frame, said attachment including a subframe surmounting said attachment main frame and connected to said last mentioned frame for tilting back and forth movement, and for longitudinal back and forth movement upon execution of its back tilting movement, and a fork lift member assembly connected to said subframe for up and down movement, the wheel being connected to said attachment frame for movement from its supporting position to a non-supporting position upon execution of the longitudinal back movement of said subframe.

References Cited in the file of this patent UNITED STATES PATENTS 2,421,472 Way June 3, 1947 2,437,806 Dempster Mar. 16, 1948 2,444,690 Almendinger et al. July 6, 1948 2,494,505 Bouchard Jan. 10, 1950 2,569,053 Healy Sept. 25, 1951 2,621,812 Lull Dec. 16, 1952 2,647,651 Vincent Aug. 4, 1953 2,711,259 Jones June 21, 1955 

